Tower for guiding pilots (5)
I believe the answer is:
pylon
'tower for guiding pilots' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for pylon that I've seen before include "Support for cables" , "Grid cable support" , "Electric cable support" , "it may mark a turning point" , "High-tension power line support" .)